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HL: Fachverband Halbleiterphysik
HL 44: 2D Materials: Electronic structure, excitations, etc. III (joint session O/HL/TT)
HL 44.1: Vortrag
Donnerstag, 12. März 2026, 15:00–15:15, HSZ/0204
Linearized augmented plane waves for low-dimensional materials — •Andris Gulans, Ernests Jansons, and Janis Uzulis — University of Latvia, Riga, Latvia
We address the challenge of efficient yet highly precise density-functional theory calculations of low-dimensional materials and present a set of tools and algorithms specific to linearized augmented plane waves (LAPW) that is implemented in the electronic-structure code exciting. First, we discuss our iterative eigensolver compatible with local and hybrid functionals. It is an extension of Davidson*s algorithm and does not require explicit Hamiltonian construction while overcoming difficulties associated with high condition numbers. The second important ingredient is the adaptively compressed exchange that represents the non-local (screened) Fock exchange via a low-rank approximation. This approach enables computational complexity as low as O(N3 logN) floating-point operations (FLOPs) with N being the number of atoms. It is a novel feature in hybrid functional calculations using LAPW as the standard approaches require O(N4) FLOPs. Finally, we introduce a cylindrical cutoff for the Coulomb interaction for handling the q=0 singularity.
Keywords: Density-functional theory; Linearized augmented plane waves; Hybrid functionals; Low-dimensional materials